1. Field of the Invention
The invention broadly pertains to a means for supporting and locating reinforcing steel in a concrete structural member. More particularly, the invention is directed to a beam chair particularly adapted to positively support and position a reinforcing steel bar in reinforced concrete beams and slabs. The beam chair is specifically adapted to accept a range of different sized reinforcing bars, and is particularly suited for locating the reinforcing bars the requisite distance inside the face of the concrete. When retained by means of the beam chair, the reinforcing bars are positively restrained against the undesirable axial and rotational movement which is apt to occur during placement of the concrete when utilizing conventional devices.
A critical element of reinforced concrete design involves the accurate placement and support of the reinforcing steel bars in the concrete structural member. It is essential that the reinforcing steel be precisely located and supported the required distance inside the face of the concrete. Failure to maintain the reinforcing steel a sufficient distance, generally 11/2 inches, inward of the face of the concrete results in detrimental oxidation of the steel reinforcement, thereby significantly compromising the integrity of the structural member and necessitating costly and extensive restoration of the structure. The support member of the instant invention addresses and eradicates the normally prevalent problem of oxidation associated with reinforced concrete members by insuring accurate location of the steel reinforcement the optimum distance inside the face of the concrete.
The detrimental effects of oxidation can only be entirely prevented when the reinforcing steel is not only accurately positioned inside the concrete face, but when the reinforcing steel is also restrained from axial and rotational movement during placement of the concrete, so as to prevent unwanted shifting of the steel from its required position. The spacer member of the present invention is uniquely capable of obtaining effective and consistent placement of the steel the necessary distance inside the face of the concrete.
Moreover, insuring the design integrity of a concrete structural member demands that the reinforcing steel bars be successfully and reliably locked in position within the concrete form to prohibit shifting of the steel when the concrete is placed. The subject support member positively prevents undesirable and potentially damaging movement of the reinforcing steel from design parameters, thereby enhancing the structural integrity of the concrete members. Consequently, the design efficiency of architects and engineers for concrete structural members is enhanced, while the potential liability for the technical designer is substantially reduced. Additionally, the attributes in design and placement of reinforcing steel realized with the present spacer member result in lower costs of construction and maintenance for reinforced concrete structures.
A further significant feature of the invention involves its impressive ease of utilization in the field by relatively unskilled personnel. Prior art methods and devices for locating reinforcing steel in beams and chairs have proved to be unsatisfactory due to the great difficulty, unreliability and complexity associated with their use. Not only do conventional chairs for beams and slabs fail to accurately and securely position the reinforcing bars, but it is also difficult for field personnel to insert the bars into such chairs. Consequently, conventional chairs invariable turn over, rotate or otherwise move out of their correct position when the steel is placed therein, and when the concrete is poured. As a result, the latter devices are problematic for these and many additional reasons, including the excessive time and labor consumed, and the inaccuries in assembly which result in improper positioning of the steel reinforcing bars within the form. The subject invention, in contrast, is not only simple to utilize, but also provides a continually reliable means for assuring precise positioning of the reinforcing steel.
The foregoing features are realized with the instant invention by presenting a spacer member for reinforcing steel bars, which spacer member lends itself for implementation in locating, supporting and retaining steel reinforcing bars the required distance inward of the concrete form and, hence, the outside face of the concrete. The invention is advantageous for its unprecedented reliability, feasibility, simplicity and economy, and is adapted to be formed so as to accommodate a variety of sizes and spacing schemes for the reinforcing steel in accordance with diverse technical specifications.